Generally speaking, all dishwashers have at least one spray arm, rotably mounted to a fixed spindle which in turn is connected to the water supply line. Water exiting under pressure from the openings in the spray arm causes the arm to rotate about the spindle as it washes and rinses the utensils in the dishwasher tub. All dishwashers have provisions for removing the spray arm for periodic cleaning. Residential dishwashers or dishwashers sold to the consuming public may employ a simple plastic wing nut threaded to the end of a spindle for hand removal and installation of the spray arm.
Commercial ware washers are operated in a severe environment and are built to more exacting standards than residential washers. The mounting of the spray arm to the spindle is typically accomplished by a closely controlled bearing/race assembly which permits accurately controlled, free-wheeling blade rotation with minimal pressure drop. It can be appreciated that with sanitizing, detergent and rinse chemicals being dispensed through the spray arms, lime and other corrosive deposits will naturally occur and require periodic cleaning, approximately weekly, of the spray arm arrangement. In addition, failure to properly clean the pump strainer in the dish washing system, may permit food particles to enter the dishwasher arm, possibly clogging some of the jets and adversely affecting rotation and operation of the dishwasher.
In one conventional spray arm arrangement, the spray arms are inserted into a spray arm hub and a bearing arrangement between the spray arm hub and a flange on the spindle is used to mount the hub in a free-wheeling manner on the spindle. A wash cap having a bearing arrangement in contact with the top of the spray arm hub is screwed on to the threaded end of the spindle to clamp the bearing assembly in place. The wash cap in turn is locked to the threaded spindle end by a set screw. When the spray arm is to be removed for cleaning, tools are required and the bearing assembly must also be dismantled. This can be especially difficult because the removal is done within the confines of the dishwasher tub.
In the unrelated connector art, a wide variety of hose connections are known. Glad hand hose connections, common on tractor trailer vehicles and railroad cars, use a rotating bayonet system for air brake lines. While such hose connections are subject to sudden forces and to vibration, the vibrations and eccentric loadings on the dishwasher spindle from the spray arms present different design considerations when considering a hand applied connect/disconnect arrangement.